Perhaps most literally, it could be a person or thing that prunes hands, like bathwater after an extended amount of time. Dishwater, perhaps. Or it could be time because as people age their skin gets slack, dry, and "pruney." It could also be a person who sucks on your fingers too much.

Slightly less literal but still mostly, it could be a person or thing that prunes hands by cutting them off. This is a painful notion.

I suppose it could also be someone who prunes and/or makes prunes by hand. I imagine it would be very boring, time consuming, and tedious.

Finally, you could go about your pruning in the garden with this little hand-held instrument. However, I think it would be best if we clarified with the hand-held modifier instead of just the hand pruner.

And that's where I come in, because I had to draw the little bugger. Observe:

Tee hee! Why you ask? Well, it was part of my final application to be a Contracted Illustrator with the U.S. Department of Agriculture for their new Tree Owner's Manual which details tree care, transportation, and proper planting techniques.